Tuesday, November 30, 2021

Sea Turtle Activity Update

Photo by Maria Lamb | First Sea Turtle Nest on Sand Dollar Island (across from South Seas Tower IV).

According to the Sea Turtle Conservancy (STC), they’ve had much interest from Marco residents since the Sea Turtle Lighting Workshop in February. They have created a waiting list for voluntary lighting evaluations, but they won’t likely get to some of the properties until sometime next yeardepending on when they can travel again. They recommend checking out the use of the Sekonic C-7000 SpectroMaster Spectrometer, to better accurately measure the light emission from the beach structures during sea turtle season. 

Just as certain wavelengths of light create danger for the sea turtles, the right type of light can also be a solution. STC recommends LED lights operating at a specific wavelengths and lower levels of visible light (lumens). According to David Godfrey, Executive Director of STC, hatchling disorientations on many properties that have switched to the new LED lights have fallen from hundreds every year to zero.  

“It’s a long-term project to replace old lights” he stated, but it is working.

The optimal sea turtlefriendly lighting wavelength is 580 nanometers or longerthat wavelength is around the yellow/orange part of the spectrum, with red following at about 700 nanometers.  

Even though a bulb might look yellow to you or me, if you look through the spectrometer, you would see the full spectrum of light. The spectrometer will tell you that you need to change that offending light bulb in your building. To the human eye, the spectrum (rainbow) goes from red (longest wavelength/least energetic light) to violet (highest energy/shortest wavelength).  

A spectrophotometer can effectively detect the rainbow contained in whatever light source it is pointed at. Some amber bulbs we see as an amber light and its “rainbow” are just yellow and orange. Other amber looking bulbs also have significant blue and green in their lightbut we can’t see it because amber is the most significant colorThe device will allow the user to determine whether it’s a “good” or “bad” amber bulb. Installing the right amber bulb will significantly reduce the hatchling disorientation.

Photo by Maura Kraus | Sea Turtle Activity (May 12).

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